An IGBT module driving circuit suitable for a high-power inverter

Abstract

The invention relates to an IGBT module driving circuit suitable for a high-power inverter. The circuit includes a full-bridge DC / DC drive power supply circuit, An optocoupler isolation circuit push-pull power amplifier, an IGBT overcurrent detection circuit undervoltage and fault protection circuits, and is characterized in that a transformer feedback overcurrent signal circuit is also provided,A transformer feedback overcurrent signal circuit includes a transformer output feedback circuit and a transformer input identification circuit, The transformer output feedback circuit samples the overcurrent signal and feeds it back to the input of the transformer. The transformer input identification circuit is connected with the undervoltage and fault protection circuit, identifies the overcurrent fault or the undervoltage fault of the power supply voltage and turns off the IGBT driving circuit and the IGBT gate overvoltage protectionthrough the optocoupler isolation circuit, and the push-pull power amplifier circuit . The invention has the advantages of simple structure, low cost, small volume, large capacity and high reliability.

Description

technical field [0001] The invention relates to an IGBT module drive circuit suitable for high-power inverters, mainly used for electrical control. technical background [0002] Inverters are widely used in wind energy, solar energy, frequency converter and other industries. In recent years, with the rapid development of new energy sources, the inverter has developed towards large capacity and high voltage. The switching device of the inverter is usually an IGBT (insulated gate bipolar transistor), and its driving circuit has two types: transformer isolation and optocoupler isolation. The larger the capacity of the IGBT module, the larger the capacity of the drive circuit is required. The higher the voltage level of the IGBT module, the higher the isolation voltage of the drive circuit is required. Therefore, the design of the drive circuit of the IGBT module is the key to the inverter. Currently, transformer-isolated drivers include Swiss CONCEPT company 2SC0435T (1700V vo...

AI Technical Summary

Problems solved by technology

However, this type of driver has a large number of components, is expensive, and has a large volume. It is not suitable for installation on the surface of the IGBT (the distance between the connecting cables is long), and the reliability is reduced.

[0003] The device that uses optocoupler isolation for the drive circuit is a wide-body optocoupler, such as HCNW2611 or HCNW3120, but this type of wide-body optocoupler used in 690V systems only has a drive optocoupler and no feedback optocoupler, which requires adding a feedback optocoupler. Increased cost, increased volume

At the same time, the drive current of the wide-body optocoupler is limited, and the maximum peak value is only 2A, which cannot meet the needs of large-capacity IGBT modules

[0004] For high-power or parallel IGBT drive circuits, the positive or negative spikes of the drive voltage due to various reasons are becoming more and more serious, causing the gate voltage to exceed the allowable voltage range of the semiconductor and causing damage to the power semiconductor. Most of the overvoltage problems were previously used. Increase the gate capacitance or use a voltage stabilizing device for peak absorption, but this suppression effect is limited, and in some cases it still cannot completely effectively suppress the overvoltage spike

For example, the literature number is CN201420397767.8, in order to solve the high frequency, large amplitude, and narrow pulse peak voltage generated by the line inductance when the IGBT is turned off, which threatens the safe operation of the switch tube, it adopts a soft The protection circuit with shutdown function and source clamp function, the soft shutdown function can adjust the soft shutdown time according to the actual demand, can effectively suppress the peak voltage generated by the parasitic inductance in the circuit, and ensure the safe and reliable operation of the IGBT, the source clamp The bit function can clamp the collector potential of the IGBT so that it does not reach a too high level. If the voltage peak is too high or too steep, the IGBT will be threatened; the document number CN201020298705.3 is aimed at the existing technology Due to the high cost of the IGBT tube device circuit and the lack of protection for the output short circuit and the short circuit of the upper and lower bridge arms, a protection module for the drive circuit based on the IGBT bridge switch topology is proposed. The protection module includes a bus detection current unit. The threshold comparison unit, the lower bridge control unit, the fault feedback unit and the MCU, the lower bridge control unit stabilizes the positive gate drive voltage of the lower bridge IGBT tube to a second voltage when the voltage signal is greater than the reference voltage threshold, and the second voltage is lower than the IGBT tube The positive gate drive voltage during normal operation. The fault feedback unit is used to feed back the fault signal to the MCU after the voltage signal is greater than the reference voltage threshold and the positive gate drive voltage of the lower bridge IGBT tube stabilizes to the second voltage, and the MCU responds according to the fault signal Stop outputting gate drive signal

It can be seen from the technical solutions of the above documents that although the drive protection circuit has a protection function, the connection of the circuit is too complicated and the production cost is too high, which leads to the lack of feasibility in the actual application link and cannot solve practical problems well.

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